Changing communications demands are transforming the existing public information network from one limited to voice, text and low resolution graphics to bringing multimedia, including full motion video, to everyone's home. A key communications transmission technology that is enabling transformation of existing public information networks to accommodate higher bandwidth needs is Asymmetric Digital Subscriber Line (ADSL), a modem technology. ADSL converts existing twisted-pair telephone lines into access paths for multimedia and high-speed data communications. ADSL can transmit up to 8 Mbps (Megabits per second) to a subscriber, and as much as 960 kbps (kilobits per second) or more in both directions. Such rates expand existing access capacity by a factor of 50 or more without new cable installations.
Asymmetric Digital Subscriber Line ADSL technology involves modems attached across twisted pair copper wiring in which transmission rates can be up to 8 Mbps downstream (to the subscriber) and from 16 kbps to 960 kbps upstream (from the subscriber), depending on line distance, can be achieved. Asynchronous Transfer Mode ATM is an ultra high-speed cell based data transmission protocol that may be run over ADSL. A Digital Subscriber Line Access Multiplexer (DSLAM) is a device that takes a number of ADSL subscriber lines and concentrates them to a single ATM line. Plain old telephone service POTS refers to basic analog telephone service. POTS takes the lowest 4 kHz bandwidth on twisted pair wiring. Any server sharing a line with POTS must either use frequencies above POTS or convert POTS to digital and interleave with other data signals.
Audio, video and other information is increasingly being distributed over networks from a single source to multiple destination points on the network. Networks have finite bandwidth capacities associated with them. Sending multiple copies of the same information to multiple destinations can become demanding on the network and does not constitute an efficient use of resources.
Accordingly, there is a need for implementing a multicast delivery service in a DSL network to make efficient use of the network.